The Hanover-Bluff Unit of the Pick-Sloan Missouri Basin Program is in north-central Wyoming near Worland. By enlarging and rehabilitating existing facilities used by the Hanover and Bluff Irrigation Districts, and constructing new canals, pumping plants, and laterals, 7,441 acres can be irrigated.

The Hanover-Bluff Unit of the Pick-Sloan Missouri Basin Program is comprised of two areas served from a common diversion on the Bighorn River: The Highland-Hanover area with 6,105 acres of irrigable land and the Upper Bluff area with 1,336 acres of irrigable land. A diversion dam across the Bighorn River diverts water to the Upper Hanover Canal, which supplies lands in the Hanover Irrigation District. This canal extends downstream on the west side of the river for 3 miles, then crosses the river in a flume to supply all Hanover land. The first 13 miles of this canal have been enlarged and are used also to supply all the land in the Highland-Hanover area.

Irrigation of land in the Highland-Hanover area is accomplished by use of five pumping plants, three of which pump directly from the Upper Hanover Canal. About 15 miles of pump canals and 12 miles of laterals serve the land.

Bluff Canal, originally constructed to supply the Bluff Irrigation District from a lower diversion on the Bighorn River, continues to be used to supply that land, as well as the Upper Bluff area. Bluff Canal was extended 1 mile to join the Upper Hanover Canal at a point 3 miles below the Hanover Diversion Dam. Initial capacity of the Bluff Canal is 92 cubic feet per second, and total length of the part of the canal used to supply Upper Bluff land is 9.1 miles.

Irrigation in the Upper Bluff area is accomplished by three pumping plants and about 8 miles of laterals

Operating Agencies

Following the completion of construction and rehabilitation, the entire unit was turned over to the Highland Hanover Irrigation District and Upper Bluff Irrigation District for operation and maintenance.

Settlement of the Bighorn River Basin and the Worland area began soon after 1879 when stockmen drove the first large herds of cattle into the area. One of the early ranches in the basin was established in 1884 on a tributary of Nowood Creek in Washakie County. The first settlement near the project was made in 1900 on No Water Creek. Early irrigation development was confined largely to small scattered tracts of land used in connection with ranching operations.

Extension of the railroad to Worland in 1906 hastened agricultural development. Since 1900, the acreage of irrigated land has increased from less than 1,000 to more than 40,000 acres.

After 1906, the population of Worland and Washakie County increased rapidly with the development of irrigation, communication, and service facilities. During the past few years, the accelerated production of petroleum and natural gas has contributed considerably to the population growth of Worland.

Investigations

The Bureau of Reclamation made a reconnaissance investigation of potential irrigation development in the Bighorn Basin in 1941. Results of this investigation are included in a report dated June 1942. Detailed surveys and investigations of the area were begun in 1949-1950, when the unit was divided into the Hanover Unit and the Bluff Unit. The investigations included detailed topographic mapping, land classification surveys, foundation explorations for canal and pump sites, land development studies, economic and repayment investigations, and preparation of cost estimates. The proposals were incorporated in the overall plan for development of the resources of the Missouri River Basin as presented in Senate Document 191. A supplemental appropriation bill that included funds for starting construction was signed by the President on August 26, 1954 and work was immediately resumed on preparation of design data. Hanover and Bluff Units were combined into one unit under this supplemental appropriation bill.

Authorization

The units were authorized as the Big Horn Pumping Units by the Flood Control Act of December 22, 1944, Public Law 534, which approved the general comprehensive plan set forth in Senate Document 191 and House Document 475, as revised and coordinated by Senate Document 247, 78th Congress, 2d session.

Construction

The original Bluff Canal was constructed in 1904 to serve 2,800 acres of land. Large-scale irrigation on the west side of the Bighorn River began with completion of the Bighorn Canal in 1907 for irrigation of 25,000 acres between Gooseberry Creek, and the Greybull River. The Lower Hanover Canal was constructed on the east side of the river in 1906 and the Upper Hanover Canal was constructed in 1910.

The first contract for construction of six pumping plants was awarded in April 1955, followed by contracts for construction of new canals and rehabilitation of other facilities. Construction of the six pumping plants was completed in 1956 and of the canals in 1957. Hanover No. 5 pumping plant and Bluff No. 1 auxiliary pumping plant were added in 1958.

Rehabilitation and Betterment

In 1975, the Highland-Hanover Irrigation District secured an emergency loan from the Federal Government to cover their portion of the cost of replacing the Hanover Diversion Dam and the No Water Creek Siphon.

The original timber-crib and rockfill diversion dam on the Bighorn River was replaced with a concrete weir diversion dam. The dam has a crest length of 250 feet and a structural height of 8.25 feet. The outlet works to the Hanover Canal were also replaced. The Upper Hanover Canal has an initial diversion capacity of 487 cubic feet per second and is controlled by two 6- foot-high by 14-foot-wide steel vertical roller gates. A third gate of equal size is located on the left abutment of the diversion dam and serves as a sluiceway.

The original steel pipe siphon structure, located across No Water Creek on the Upper Hanover Canal, was replaced with a 120-inch inside diameter reinforced concrete pipe siphon with a total length of 2,264 feet. The concrete pipe siphon has a capacity of 500 cubic feet per second and is directly upstream of Highland-Hanover Irrigation District Pumping Plants No. 2 and No. 5.

In 1990, the Highland Hanover and Upper Bluff Irrigation Districts entered into Rehabilitation and Betterment contracts with Reclamation, associated with reshaping and relining of main irrigation canals, conversion of over 5000 feet of laterals to buried pipe, construction of desilting basins at four pumping plants, replacement of pumping plant electrical equipment, and rehabilitation of moss removal equipment at two of the plants.